Airbus will launch two pairs of optical satellites, one in 2020 and one in 2021, to form a constellation with two orbital planes enabling two revisits per day. The satellites will have a 30cm resolution, a 14km swath, and orbit at 620km altitude. They will leverage the EDRS data relay satellites for ultra-fast tasking and downlink. The constellation is called Pleiades Neo, and will image 2 million km² per day. The rest of the article details how this fully private constellation is a change compared to the previous French public-private observation satellites, and how information about the constellation has emerged since the announcement in 2016.
Airbus Defense & Space announced in September 2016 that it will launch a constellation of 4 Very High Resolution (VHR) optical earth observation satellites, in 2020 and 2021. This will be a follow-on to the Pléiades constellation, which comprises two agile, 70cm resolution satellites, launched in 2011 and 2012. Unlike Pléiades, which was a public-private partnership between Airbus (the prime contractor), Thales (which provided the instruments) and the French Ministry of Defense, this new constellation will be entirely financed by Airbus, to the tune of 550M€
According to the press release, “Pléiades system features will be improved to match the market requirements expected to be the norm at the time of launch”, which I speculated to mean the resolution will be improved to 30cm, to match the resolution of the Worldview 3 and Worldview 4 satellites owned by Airbus’ main competitor, Digital Globe. Airbus has since confirmed the 30cm resolution. This is coherent with the studies on the design of 20 to 30 cm resolution satellites carried out by CNES, the French space agency.
These studies led to the ARCTOS concept by Airbus, with a 30cm resolution from 700km up, a 20km swath, and a small enough mass to be launched from a Vega launcher thanks to a lightweight 1.5m SiC mirror. Resolutions higher than 30cm are much more difficult to achieve. Besides, the release calls the constellation “VHR”, which is between HR (around 70cm, like Pléiades) and EHR (extremely high resolution, around 20cm) in the French classification of resolution. Airbus is also the prime contractor for CSO, a military EHR satellite to be launched around 2020, but this satellite fly will relatively low in order to achieve this resolution, so the technology is probably not mature for an EHR satellite at 700km altitude. CNES, Airbus and Thales are also working together on the OTOS concept, which would use adaptative optics to correct for mirror deformations.
Consequently, at the time of the announcement, I estimated the constellation would be made of four 30cm resolution satellites. Since the release states it will provide “intra-day” revisit, this means the constellation will have two orbital planes: from orbits around 700km, two agile satellites on the same orbital plane are required to provide same-day revisit, so two planes are needed.
This constellation will help Airbus catch up with Digital Globe, but the US company has already announced it is designing its next-generation constellation, which will be made up of six 1m-resolution satellites build and operated by the United Arab Emirates and a high-resolution component owned by Digital Globe. The Emirati satellites will provide a high temporal revisit, enabling to detect changes and then cue the higher resolution satellites to characterize these changes. The former are scheduled for launch in 2018 and 2019, around the same time Digital Globe plans to seriously invest in the latter.
Finally, the release mentions the constellation will be “dual”, which probably means it will be a dual-use civilian and military constellation, giving the French Ministry of Defense tasking priority when required. This would considerably increase the temporal revisit capability of the French reconnaissance system.
Source:
https://satelliteobservation.net/2016/09/15/the-airbus-very-high-resolution-constellation/
